1. Field of the Invention
This invention relates generally to a housing for electronic components and more particularly to a housing for remote interface units.
2. Discussion of the Related Art
Remote interface units provide an electrical interface between a host processing unit and remote devices. Typically, the remote devices control or monitor a process. The remote device supplies status signals, both in digital and in analog form, and accepts control signals determined by the status signals.
In the related art, the remote interface units provide predetermined functions and have defined operational characteristics. In addition, the location is typically known and so the appearance can be adapted to the expected environment.
The capabilities and physical appearance of the remote interface units have, in the past, been relatively fixed. However, recently small personal computers have been provided with impressive capabilities for data signal manipulation. These data processing systems are being increasingly utilized in process control and monitoring applications. The smaller data processing systems can even be located in the vicinity of the process being controlled or monitored. Furthermore, with the diminishing costs of processing capabilities, many new applications for process control are being developed. The new applications require additional dedicated units with increased flexibility and/or the possibility of progressive expansion of capabilities.
A need has therefore been felt for a remote interface unit that can be located in a variety of environments and has the capability of expansion and/or adjustable signal manipulation characteristics. The requirements for the housing of a requisite unit include an appearance suitable for a plurality of environments, ease of disassembly and the requirement of easy addition or exchange of portions of the unit. For example, it is desirable to have expansion modules that can be added or replaced without the use of hand tools to minimize accidental damage to the electrical apparatus by the tools.